1. A window to the outside or surface.
2. A skeleton with basic gear
3. Rats or other vermin eating scraps of remaining meals
4. A monster, such as a dungeon inhabitant or spy.
5. A wild animal.
6. A small tool or key hidden under a mattress.
7. A baby.
8. A secret hidey-hole, filled with food, or the start of a tunnel to freedom (perhaps even completed!)
9. Coins or a small piece of jewelry.
10. A stash of porn, perhaps monster-girls?
11. Makeshift weapons, such as a shank.
12. A prisoner, ripe for recruitment or to replace a player character!